Case for 2014 Dermpedia Hematopathology Conference. What kind of papulonecrotic disease is it?

A 8-year-old boy has recurrent skin lesions with crusted ulceration on his face and limbs. He has similar rash happened intermittently since one year old. Blood tests including CBC, CRP, ANA, RF, C3, C4, HIV, phogocyte functions have been done but all showed normal findings.